A conventional beverage can as shown in FIG. 7 includes an end over C having a tab T secured with a pulling ring P and normally sealing a drinking opening O formed on the cover C, whereby upon pulling of the ring P and the tab T to disclose the opening O for drinking purpose, the tab T, if not being suitably disposed, will cause environmental protection problem.
Even though another conventional can as shown in FIG. 8 may prevent a free disposal of the tab T for the reason of environmental protection, the tab T once biased downwardly inwardly into an interior of the can by pulling the pulling ring P to disclose the drinking opening O may decant dust particles D previously accumulated on the cover and tab surface into the can beverage, causing contamination and hygienic problems to the beverage or materials stored in the can and possibly influencing the user's health.